A Box-Maker’s Sled

Precise crosscut and mitering capability make this table saw jig twice as nice

I enjoy making small boxes. Coming up with different designs is just as challenging as the actual construction work. One thing that doesn’t change is the requirement for precise cuts. A tiny gap may not be an issue in a large project, but it can be painfully noticeable in a small box. I rely on this table saw sled for making perfectly square and mitered cuts in small parts. The sled has a single runner that can be used in both table grooves. In one groove, you’re cutting at 90°. In the other, you make 45° bevel cuts. In both applications, the jig’s base and fence provide zero clearance with the saw blade. In addition to reducing tearout, this feature makes it easier to align precise cuts.

My table saw has a right-tilting blade. If your saw’s blade tilts left, you’ll need to relocate the runner to slide in the saw’s left groove when making the first cut. Be sure to make the initial 90° and 45° cuts in your jig with the same sharp, finish-cutting blade you’ll have in the saw when putting the jig to use.

Start with a base, then add rails, runner, and fence

When making your jig, use dead-flat plywood, and make sure to mill your rail and fence stock straight and square. This jig will work just as well if made smaller, but a larger size might put too much torque on the single runner. 

The fence that I’m using here is quite a bit longer than you need for cutting small parts. The extra length makes the sled more versatile by enabling me to cut longer parts to uniform length. 

The runner for this jig is an 18"-long Miter Slider from Incra (see Buyer’s Guide, p. 69). Like other aftermarket runners, this one can be adjusted to slide easily but without slop in the table groove. 

The runner’s location on the underside of the base depends on the distance between your saw table grooves and the blade. Position it to extend the base an inch or so beyond the blade for your first 45° miter cut (see bottom photo, facing page).

You’re supposed to attach the Miter Slider with machine screws that are installed through the top of the base. But I’ve found that it’s easier and no less effective to mount the bar by driving pan-head screws through the mounting holes and into the underside of the base.

NOTE: Replace the fence if the zero-clearance kerfs become inaccurate due to long-term use or a blade change. Alternately, you can attach a strip of wood to the old fence and make two new zero-clearance cuts.

Begin with the bar. With this adjustable Miter Slider bar, you fine-tune the fit by turning a pair of screws with an Allen wrench. Make sure your bar slides smoothly, and without any side-to-side slop.
Attach the runner. Glue the front and rear rails to the plywood base, then attach the bar with #6 × 3⁄4" pan screws. Position the bar with enough material on one side so that the saw blade can create the mitered edge.
Make the first cut. Raise the blade no more than 11⁄2" above the table for this initial cut. (With a right-tilting blade, the sled’s runner should be in the right-hand groove.)

Install the fence. Insert a snug-fitting strip of wood in the kerf, then register a drafting triangle against the strip and the fence while clamping the fence in place. Here I’ve clamped both ends of the fence to the base. Once the fence is clamped, flip the jig over, and secure the fence with a screw near each end. Make a test cut in some straight-edged stock to confirm that the fence is square to the blade, and fine-tune the fence angle if necessary. When you’ve got it right, anchor the fence by driving two screws on each side of the kerf.

Make the miter cut. Raise the blade about 11⁄2" above the table and tilt it to exactly 45° to make this cut. When you’re done, you’ll have a zero-clearance edge in the base, and a zero-clearance kerf in the fence. It’s time to make some boxes (See p. 24). 

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